The classic rabbis thought individuals had a good inclination and an evil inclination (yetzer tov and yetzer harah) in them, but that “you can choose between them.” When we are seriously tempted, do we truly have the ability to say no? Selfishness comes naturally to us, but so do cooperation and generosity. Where do God and mitzvot fit into our decision-making? Most fundamentally, how much free will—if any—do we have? Reform Rabbi Ralph Mecklenburger was ordained in 1972 and served congregations in San Francisco, Ann Arbor, and Fort Worth, Texas. For some years, as the revolution in our understanding of how our brains function advanced, he has been studying its implications for religion. His book, Our Religious Brains: What Cognitive Science Reveals about Belief, Morality, Community and Our Relationship with God, came out in 2012.